Various network-based applications allow a user to view the current geographic locations of the user's friends or family. For example, where both parties have given permission, a parent may check the whereabouts of a child by using such an application to view the location of a device physically proximate to the child. In order to make these applications useful, the device, often a mobile phone, must constantly, for example every minute or less, send location updates to a server. Thus the mobile phone must continuously expend processing power to use a GPS receiver to identify the location. This may result in significant drain on the power supply of the client device.
This drain may be even more significant where the GPS receiver is unable to immediately receive data from GPS satellites. For example, GPS works best outside, where reception from the satellites is most effective. If a device is located within a building, the GPS receiver may not be able to receive data from the satellites as the building may interfere with the signals. As many users spend a significant portion of the day inside of buildings, their devices may be continuously attempting to obtain information from GPS satellites unsuccessfully.